rockchip: rk3399: Add Rockpro64 board support

Add initial support for Rockpro64 board.

Specification
- Rockchip RK3399
- 2/4GB Dual-Channel LPDDR3
- SD card slot
- eMMC socket
- 128Mb SPI Flash
- Gigabit ethernet
- PCIe 4X slot
- WiFI/BT module socket
- HDMI In/Out, DP, MIPI DSI/CSI, eDP
- USB 3.0, 2.0
- USB Type C power and data
- GPIO expansion ports
- DC 12V/2A

Commit details of rk3399-rockpro64.dts sync from Linux 5.1-rc2:
"arm64: dts: rockchip: rockpro64 dts add usb regulator"
(sha1: 6db644c79c8d45d73b56bc389aebd85fc3679beb)

'Akash' has sent an initial patch before, so I keep him as board
maintainer and I'm co-maintainer based on our conversation.

Signed-off-by: Akash Gajjar <akash@openedev.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/rockpro64-rk3399_defconfig b/configs/rockpro64-rk3399_defconfig
new file mode 100644
index 0000000..90bcaed
--- /dev/null
+++ b/configs/rockpro64-rk3399_defconfig
@@ -0,0 +1,60 @@
+CONFIG_ARM=y
+CONFIG_ARCH_ROCKCHIP=y
+CONFIG_SYS_TEXT_BASE=0x00200000
+CONFIG_SPL_LIBCOMMON_SUPPORT=y
+CONFIG_SPL_LIBGENERIC_SUPPORT=y
+CONFIG_SYS_MALLOC_F_LEN=0x4000
+CONFIG_ROCKCHIP_RK3399=y
+CONFIG_ROCKCHIP_SPL_RESERVE_IRAM=0x50000
+CONFIG_DEBUG_UART_BASE=0xFF1A0000
+CONFIG_DEBUG_UART_CLOCK=24000000
+CONFIG_SPL_STACK_R_ADDR=0x80000
+CONFIG_DEBUG_UART=y
+CONFIG_NR_DRAM_BANKS=1
+CONFIG_DEFAULT_FDT_FILE="rockchip/rk3399-rockpro64.dtb"
+# CONFIG_DISPLAY_CPUINFO is not set
+CONFIG_DISPLAY_BOARDINFO_LATE=y
+CONFIG_SPL_STACK_R=y
+CONFIG_SPL_STACK_R_MALLOC_SIMPLE_LEN=0x10000
+CONFIG_CMD_BOOTZ=y
+CONFIG_CMD_GPT=y
+CONFIG_CMD_MMC=y
+CONFIG_CMD_SF=y
+CONFIG_CMD_USB=y
+# CONFIG_CMD_SETEXPR is not set
+CONFIG_CMD_TIME=y
+CONFIG_SPL_OF_CONTROL=y
+CONFIG_DEFAULT_DEVICE_TREE="rk3399-rockpro64"
+CONFIG_OF_SPL_REMOVE_PROPS="pinctrl-0 pinctrl-names clock-names interrupt-parent assigned-clocks assigned-clock-rates assigned-clock-parents"
+CONFIG_TPL=y
+CONFIG_ENV_IS_IN_MMC=y
+CONFIG_ROCKCHIP_GPIO=y
+CONFIG_SYS_I2C_ROCKCHIP=y
+CONFIG_MMC_DW=y
+CONFIG_MMC_DW_ROCKCHIP=y
+CONFIG_MMC_SDHCI=y
+CONFIG_MMC_SDHCI_ROCKCHIP=y
+CONFIG_DM_ETH=y
+CONFIG_ETH_DESIGNWARE=y
+CONFIG_GMAC_ROCKCHIP=y
+CONFIG_PMIC_RK8XX=y
+CONFIG_REGULATOR_PWM=y
+CONFIG_REGULATOR_RK8XX=y
+CONFIG_PWM_ROCKCHIP=y
+CONFIG_BAUDRATE=1500000
+CONFIG_DEBUG_UART_SHIFT=2
+CONFIG_SYSRESET=y
+CONFIG_USB=y
+CONFIG_USB_XHCI_HCD=y
+CONFIG_USB_XHCI_DWC3=y
+CONFIG_USB_EHCI_HCD=y
+CONFIG_USB_EHCI_GENERIC=y
+CONFIG_USB_HOST_ETHER=y
+CONFIG_USB_ETHER_ASIX=y
+CONFIG_USB_ETHER_ASIX88179=y
+CONFIG_USB_ETHER_MCS7830=y
+CONFIG_USB_ETHER_RTL8152=y
+CONFIG_USB_ETHER_SMSC95XX=y
+CONFIG_USE_TINY_PRINTF=y
+CONFIG_SPL_TINY_MEMSET=y
+CONFIG_ERRNO_STR=y